// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/webui/url_data_source_impl.h"

#include <utility>

#include "base/bind.h"
#include "base/memory/ref_counted_memory.h"
#include "base/strings/string_util.h"
#include "content/browser/webui/url_data_manager_backend.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/url_data_source.h"

namespace content {

URLDataSourceImpl::URLDataSourceImpl(const std::string& source_name,
    URLDataSource* source)
    : source_name_(source_name)
    , backend_(nullptr)
    , source_(source)
{
}

URLDataSourceImpl::~URLDataSourceImpl()
{
}

void URLDataSourceImpl::SendResponse(
    int request_id,
    scoped_refptr<base::RefCountedMemory> bytes)
{
    if (URLDataManager::IsScheduledForDeletion(this)) {
        // We're scheduled for deletion. Servicing the request would result in
        // this->AddRef being invoked, even though the ref count is 0 and 'this' is
        // about to be deleted. If the AddRef were allowed through, when 'this' is
        // released it would be deleted again.
        //
        // This scenario occurs with DataSources that make history requests. Such
        // DataSources do a history query in |StartDataRequest| and the request is
        // live until the object is deleted (history requests don't up the ref
        // count). This means it's entirely possible for the DataSource to invoke
        // |SendResponse| between the time when there are no more refs and the time
        // when the object is deleted.
        return;
    }
    BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
        base::Bind(&URLDataSourceImpl::SendResponseOnIOThread,
            this, request_id, std::move(bytes)));
}

bool URLDataSourceImpl::IsWebUIDataSourceImpl() const
{
    return false;
}

void URLDataSourceImpl::SendResponseOnIOThread(
    int request_id,
    scoped_refptr<base::RefCountedMemory> bytes)
{
    DCHECK_CURRENTLY_ON(BrowserThread::IO);
    if (backend_)
        backend_->DataAvailable(request_id, bytes.get());
}

const ui::TemplateReplacements* URLDataSourceImpl::GetReplacements() const
{
    return nullptr;
}

} // namespace content
